Terminals may be generally classified as mobile/portable terminals or stationary terminals according to their mobility. Mobile terminals may also be classified as handheld terminals or vehicle mounted terminals according to whether or not a user can directly carry the terminal.
As such functions become more diversified, the mobile terminal can support more complicated functions such as capturing images or video, reproducing music or video files, playing games, receiving broadcast signals, and the like. By comprehensively and collectively implementing such functions, the mobile terminal may be embodied in the form of a multimedia player or device.
Particularly, as functions of a mobile terminal are getting diversified, authentication functions using user's personal information for product purchases, various credit payments, security required site accesses and the like are performed through the mobile terminal as well. Yet, in case of performing user authentication by inputting such personal information, a security problem such as leakage of user's personal information and the like may be caused. And, it may be also inconvenient to input passwords to various authentication certificates one by one.
To support and increase the mobile terminal functions, it may be able to consider the improvement of structural parts and/or software parts of the mobile terminal.
For the use convenience and the security safety, a user authentication system using user's unique body elements such as fingerprint, iris, face and the like is attempted on a mobile terminal. To this end, a recognition module for a user body element is added to a mobile terminal by hardware and software improvement is attempted to operate the added module.
However, although the user authentication system is applied, it may cause a problem that a recognition rate varies according to a user environment. Moreover, in case that a user body needs to approach a mobile terminal in a prescribed range in order to raise a recognition rate, a user may be reluctant due to personal inclination.
Moreover, regarding iris recognition, when an iris is captured for the iris recognition by a camera of a mobile terminal, it is inconvenient for a user to adjust a proper distance between the user and the camera by guessing a focus while watching a camera preview screen of the mobile terminal in order to obtain a focused iris image in a proper size.